1. Field of the Invention
The present invention relates to an apparatus and method for capturing photoresist stripping chemicals from an exhaust system and, more particularly, to such an apparatus and method utilizing a combination of throttling, cooling and carbon adsorption.
2. Description of the Related Art
Various toxic chemicals, including solvents and organic compounds, are produced during semiconductor and integrated circuit manufacturing operations. The toxic organic compounds include carbon monoxide, carbonic acid, metallic carbides of carbonates and ammonium carbonate. For example, photoresist processing is a semiconductor manufacturing procedure that requires the use of strongly acidic solvents. Photoresist processing produces a solvent mist which is collected in the manufacturer's exhaust system. For some photoresist processing methods, the solvent released into the exhaust system is very close to its flash point, creating a dangerous condition and making the removal of the solvent difficult.
Furthermore, toxic solvents and organic compounds, including waste solvents, are injurious to the environment and their emission into the environment is regulated by various state and federal government agencies. For example, the amount of the compounds that are produced by a semiconductor manufacturer is limited. Furthermore, the compounds and solvents cannot be stored or discarded in a manner that allows evaporation of the materials into the atmosphere.
In addition, many of the toxic compounds and solvents are highly acidic organic vapors that, if allowed to enter the general exhaust system of a manufacturer, causes corrosion and leaking of the system ducts and fills the duct work with a soluble sludge.
Semiconductor manufacturers have used various methods to reduce emissions of organic materials, including incinerators, water scrubbers and adsorption systems.